1. Field of the Invention
The present invention relates to the management of hydrocarbons released below the surface of a body of water. More particularly, the invention relates to the management of hydrocarbons released from a subsea oil/gas well, or from casings or risers coming from the well. More particularly still, the invention relates to the use of dispersants applied in a subsea environment to reduce the ill effects of the uncontrolled release of hydrocarbons.
2. Description of the Related Art
Once an oil spill has taken place, countermeasures are taken to try to reduce the adverse effects of the spilled oil on the environment. Dispersants, chemicals that are applied directly to the spilled oil in order to remove it from the water surface, are one kind of countermeasure. Dispersants are generally less harmful than the highly toxic oil leaking from the source and biodegrade in a much shorter time span.
When dispersants are applied to surface oil slicks, they act to break up the slicks and move the oil, in the form of tiny droplets, from the water surface down into the water column (the volume of water extending from the surface to the bottom). In a typical scenario, the dispersant is applied to the water surface. Next, molecules of the dispersant attach to the oil, causing it to break into droplets. Thereafter, wave action and turbulence disperse the oil-dispersant mixture into the water column, so that the oil that had been concentrated at the surface is diluted within the water column.
The forgoing is especially useful in instances where oil is released at or near the surface of the water, such as a ruptured tank on a vessel carrying crude oil or a leak from a well at the upper end of a tubing string. The presently available methods, however, are limited to treatment of the oil once it is on the surface and is not helpful in treatment of the oil at its subsea source. What is needed is a more effective way to treat well spills that take place in a subsea environment at the source of the spill to prevent hydrocarbons from spreading throughout the water columns before it hits the surface and spreads over a greater area before it is contained.